Both are techno economists, forestry and wood processing their speciality.
South Africa's economy was in nosedive when Margriet spotted an article "this big" (she holds thumb and forefinger mere centimetres apart) announcing New Zealand was offering scholarships in sawmill productivity and science, one was at Rotorua's Forestry Research Institute, now Scion.
Research on Rotorua began. "The only thing I could find about it was another tiny piece [there's that finger demo again] in the Encyclopaedia Britannica saying it had geysers, forestry and an average 12km/h wind speed. Growing up in Cape Town where it's often as windy as Wellington, that was a big draw."
Louw secured the FRI scholarship; with two young children, Margriet stood back from formally applying.
"I'd just finished my thesis on wood processing research management so I did wangle it so his application included his wife was also a techno economist."
With their children settled in their new environment, Margriet was inveigled into teaching economics at Girls' High.
"I'd only been there a few days when Immigration threatened to deport me, I didn't have a work permit."
Such brief employment meant no pay packet, something she now finds hilarious but not so funny at the time.
Once the permit business was sussed, FRI embraced her scientific, management and economic know-how. Her roll call of degrees includes a PhD and the South African equivalent of an MBA.
The husband and wife became FRI scientist fixtures.
That was until pressure went on in 1989 with government demands that such organisations become business-focused Crown Research Institutes.
Wise heads knew Margriet was the ideal appointee to lead the Wellington-based establishment unit.
"I took a deep breath and thought 'what on earth does this mean to start a new government department?' I'd never even been in a minister's office."
For the next six years she commuted to the capital.
"I'd come back and sleep at Maketu for a night or two, then Rotorua for a night or two."
Acquiring a beach place had confirmed the Theron-Van Wyks' Kiwification.
From leading the establishment unit, Margriet transitioned to the Ministry of Research and Technology (MoRST) as science review manager.
But home remained paramount; learning the hunt was on for dean of the then Waiariki Institute of Technology's forestry faculty, her hand shot up.
"I was about to fly back for the interview from Christchurch when I saw the headline 'Sawmill burns down', it was Waiariki's."
The fire didn't snuff out the position, it added to the challenge that came with confirmation the job was hers.
"The first year was a struggle securing the $2.5 million insurance money, that figure will be stuck in my mind forever".
With additional funding, the mill was rebuilt.
She had dual workplaces, the Timber Technology Centre at Waipa and the FRI campus.
In a conversation that swings from era to era, Margriet harks back to her appointment as the district council's rep on the Rotorua High Schools Board.
"I'd been on the Otonga, Rotorua Intermediate and Western Heights High school committees, chaired the Boys' High school committee before the introduction of boards of trustees."
Fast forward to her 2004 retirement. "I had so many other interests on the go I found it easy. I taught economics night classes at Waiariki, accountancy in the afternoons at Boys' High."
An invitation came to join the New Zealand Speech and Drama Examination Board. "They needed my marketing and financial input."
This is no boast; it's a statement of fact. She was on the board for 12 years.
Another post-workforce appointment was patron of WITSA , Waiariki's Student Association.
Today it's the Multicultural Society her name's most frequently linked with. Her involvement with new migrants began with its forerunner, the Ethnic Council.
Her long association with the Chamber of Commerce inspired her to enter the council in last year's business awards.
"Blow me, we won the community organisation category. Did you know out of Rotorua's population of 70,000-75,000, 12,000 were not born in New Zealand?"
No, Margriet, we didn't and bet we aren't alone being astonished by that figure.
And who can disagree with her that such diversity enriches all of us?
Another commitment's teaching new migrants, refugees included, to become confident speakers and understand Māori culture.
Becoming an accredited court interpreter translating Afrikaans into English and vice versa, covering an area from Manukau across to Gisborne and west to New Plymouth, is a recent addition to this go-getter's qualifications.
"A lot involves mediation matters."
We'd have been surprised if Margriet told us she wasn't a Rotarian. Of course she is and not just any Rotarian, she was the "rather conservative" Rotorua club's first woman president.
A Geyser Foundation founding trustee, she's now an ambassador and has represented the local organisation on the Community Federation of New Zealand Trusts.
Surely, with a working life that began in a baking powder factory, it was a portent that Margriet Theron's life was one that was sure to rise but how on earth has she achieved so much?
"It's been a privilege not to have been the main income earner in our family, it's given me the freedom to take more risks."
FACTBOX:
MARGRIET THERON:
Born: Cape Town, 1942
Education: Local primary and secondary schools, Stellenbosch University, University of South Africa
Family: Husband Louw VanWyk, daughter Marie (Melbourne), son Jacques (Sydney), five grandchildren
Interests: Family, people, gardening, growing South African wildflowers, watching American politics on CNN, reading financial articles on consumerism, providing Facebook information to South Africans living in New Zealand, welcoming new settlers. "Walking my dog in the Redwoods every day religiously at 9.30am, cyclones or heat waves." Tourism. "I'm a tour guide for Road Scholars. elderly, well-educated Americans who want lectures at places they visit."
On Rotorua: "We collaborate, networking in Rotorua's better than anywhere else."
Personal philosophy: "Will it matter six months from now?"
